Reading around Nokia forums, It seems that accessing Cell-ID and related info from Nokia S40 series phones is virtually impossible unless your Midlet is signed, and even this would work only for S40 3rd Edition FP1 and above.
I tried the following on a Nokia S40 Dev Platform 2 phone , using Java ME:
System.getProperty("com.nokia.mid.cellid");
however the value returned was null.
Is there any work around to this, can the Cell-ID be read by other methods, like Modem AT(I guess this will only work with a phone connected to the pc), Sim application Toolkit or other?.